Interpretive Summary: This work describes the isolation of a new bacterial species found during a study to examine microorganisms from retail ground beef. This new species was found to be most closely related to a group of bacterial called, Peptoniphilus, because of their ability to grow on a protein source known as peptone. Unlike other Peptoniphilus bacteria, this strain has the unique ability to degrade an unusual type of modified amino acid, suggesting that it might have potential biotechnological relevance. This research improves our understanding of bacterial relatedness and is expected to have impact in areas food safety, agricultural, biomedical science, and biotechnology.

Technical Abstract:
Strain NRRL B-23883 was isolated from retail ground beef as part of a study on the genetic diversity of Clostridium perfringens. The strain was found to be a strictly anaerobic, gram-type positive coccus that was able to utilize peptone as a sole carbon source. Subsequent to sequencing the 16S ribosomal RNA gene, it was found that the strain’s closest relatives were in the genus Peptoniphilus but it was substantially different from the closest recognized species by nearly 10% sequence divergence. The strain was also found to be closely related (>99% sequence similarity) to a strain of uncultured bacteria that was sequenced from a 16S ribosomal RNA gene clone library constructed to characterize the bacterial community of feces from captive specimen of spotted hyaena. Strain NRRL B-23883T shared the peptidoglycan type A4-beta, L-Orn – D-Glu with members of the genus Peptoniphilus. Further phenotypic analysis revealed that strain NRRL B-23883 was able to utilize glycyl-L-methionine as a sole carbon source, in contrast to other Peptoniphilus species. Therefore, we propose to recognize this strain as Peptoniphilus methioninivorax with type strain NRRL B-23883T (= DSM 22461T).